The present invention relates to optical beam steering and more particularly to an acousto-micro-optic deflector for performing such optical beam steering.
High resolution steering of optical beams is of significant interest for a variety of applications, including free space laser communication, laser illumination, laser designation, laser radar, pointing and tracking, and remote optical sensing. Current steering systems commonly rely on mechanical gimbals. Such gimbal-based systems are slow and prone to mechanical failure.
It is highly desirable to have high resolution and fast agile beam steering without reliance on mechanical gimbals. Existing fast non-gimbaled solutions include acousto-optics, liquid crystals, electro-optics, micro-optics, small and fast galvanometer or magnetic mirrors, and micro-mirror arrays made by microelectromechanical system (MEMS) technologies. In their current configurations, none of these existing fast non-gimbaled solutions fully meets the needs of many potential users for agile beam steering.
In practice, in order to cover large total angular ranges, beam deflector devices have cascaded fast steering elements with a larger, slower element, for fine and coarse beam steering, respectively. For example, a fast magnetic or galvanometer-driven fine scanner is placed in tandem with a larger gimbaled mirror, resulting in a higher resolution scanner system, but with some applications issues.
Conventional mirror based cascade systems have a number of shortfalls, such as reliance on gimbals, slow effective response, and being relatively large in overall size and weight. Other combinations of fast beam deflectors have suffered from the tradeoff between speed and angular range. A problem common to all conventional tandem/cascaded beam deflectors has been the transient loss of the beam on target during the time that the fine scanner resets back to its starting position. This problem is sometimes referred to in the art as a xe2x80x9cflybackxe2x80x9d problem.
Depending on the speed of the target/receiver, a flyback condition can happen many times a second, and can be a serious disadvantage for applications such as high bandwidth free space laser communication with a moving target. Such periodic transient loss of the beam on the target can cause the loss of substantial amounts of data, increase bit errors, and possibly lose target contact if the target is moving rapidly.
An acousto-micro-optic deflector (AMOD) is provided. This device uses a special combination of an acousto-optic deflector (AOD) and a micro-optic deflector (MOD). The combination is driven such that the entire field of regard of the device is accessible, and continuous contact with the target point is maintained.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.